Method and device for improved maintenance of luminaires

ABSTRACT

An indicating device for detecting the decrease in fluid pressure in the interior of a luminaire includes, in one embodiment, a pressure sensitive switch in a chamber in fluid communication with the luminaire interior. The switch is operated to actuate an indicator without turning off the luminaire whenever the pressure in the luminaire falls below a predetermined level. Also disclosed is an inflatable hollow gasket for creating a fluid-tight seal between the housing and cover and a device for indicating an excessive loss of pressure in the gasket interior.

United States Patent [191 Stein [111 3,840,733 1 Oct. 8,1974

[ METHOD AND DEVICE FOR IMPROVED MAINTENANCE OF LUMINAIRES [76] Inventor: Marcel Stein, 560 Riverside Dr., New York, NY. 10027 [22] Filed: Aug. 14, 1972 211 Appl. No.: 280,334

[52] U.S. Cl 240/112 R, 240/25, 240/4155,

200/81 R, 277/34.3 [51] Int. Cl. F215 1/10, Fl6j 15/46 [58] Field of Search 240/112, 25, 41 R, 41.5, 240/4155, 41.35; 200/81 R, 83 R, 83 B; 277/34, 34.3

[56] v References Cited UNITED STATES PATENTS 2,347,055 4/1944 Johnson 240/41 R 2,700,196 1/1955 Panhard 277/34 X 2,747,078 5/1956 Kennedy et a1. 200/81 R X 2,749,536 6/1956 Sperling 200/83 R X 2,785,824 3/1957 Reeves 277/34 X 3,187,171 6/1965 Trautner et a1 240/4155 X 3,240,038 3/1966 Schwegler 277/34 UX 3,325,637 .6/1967 Honda 240/4155 X Primary Examiner-Robert P. Greiner Attorney, Agent, or FirmSandoe, Hopgood & Calimafde 57 I ABSTRACT An indicating device for detecting the decrease in fluid pressure in the interior of a luminaire includes, in one embodiment, a pressure sensitive switch in a chamber in fluid communication with the luminaire interior. The switch is operated to actuate an indicator without turning off the luminaire whenever the pressure in the luminaire falls belowa predetermined level. Also disclosed is an inflatable hollow gasket for creating a fluid-tight seal between the-housing and cover and a device for indicating an excessive loss of pressure in the gasket interior.

8 Claims, 6 Drawing Figures Experience shows that the light transmitting output of lamp-luminaire setups deteriorates with time due to dirt deposits on the light transmitting and reflecting surfaces. In addition, the reflector materials often decompose due to the corrosive action of aggressive gases entering the interior space of luminaires. It was found, eg that the reflectors of luminaires near bus stations are among the most damaged this way. All these occur in spite of protective covers and deflectors supposed to seal the interior of the luminaires by means of rubber or plastic gaskets.

It seems to be practically impossible to control the maintenance of hardly accessible luminaires under present conditions and the deterioration of the lighting output of a lamp-luminaire setup can be only detected when a substantial reduction in the illumination of the illuminated objects becomes obvious.

Due to the increased efficacy of high intensity lamps, to the request for the reduction of glare, and to the prevention'of'accidents in connection with lampposts on highways and streets the present tendency in the design of street and roadway lighting systems is to reduce the number of lampposts. These, however, must have greater mounting heights the maintenance of which is linked with greater costs.

Therefore, it seems to be desirable from every aspect to provide a more efficient protection of the inner parts of the luminaires against dirt deposits and corrosion than up to now. Also an easy control ofthe effectiveness of protective measures without direct inspection of the inner parts is needed.

An analysis of the inflowof dirt and of aggressive gases into the. luminaires is as follows: Could a permanently tight seal be provided between the glass or plastic cover and the luminaire body, no dirt or gas would have access into the luminaire. An uptight closure can occur either at the installation of the rubber or plastic gasket or later. Even a slight displacement of the gasket or a small discontinuity on its surface at the closure of the cover can result in an inadvertantly uptight closure. The deterioration of the material may cause leakages later which are undetectable by present means.

The temperature of the air enclosed increases while the lamp is in operation whereby the air pressure inside the luminaire increases according to Boyles law in case of tight sealing. Some excess air is discharged from the luminaire in the case of uptight closure during this period. However, cooling air contracts when the lamp is switched off creating a depression inside the luminaire. This phenomenon called breathing of the luminaire causes some air to be sucked in that may possibly be contaminated by humidity, dirt and aggressive gases, if

the gasket does not close tightly. Due to repeatedbreathing actions more and more dirt accumulates on the light transmitting surfaces of the lamp and other parts. The reflector is obstructed in a similar way, and in addition is attacked by the aggressive gases. Its deterioration is enhanced by the high temperatures near the top of the luminaire when the lamp is again in operation.

It is common practice to clean the inner and outer parts of luminaires at regular intervals in order to restore the original maximum light-transmitting properties. However, gradually less and less light is transmitted between these cleanings and the loss in illumination can be substantially under polluted ambient air conditions. The increase of the cleaning frequency is in most cases prohibitive due to excessive maintenance costs.

In order to prevent permanently the dirt, humidity and aggressive gases from entering the inner space of luminaires, I propose to put the latter under permanent low gas pressure. The magnitude of this initial gas pressure will depend on the actual ambient temperature, the lowest ambient temperature on record at the site, and the type of the lamp and of the luminaire. No polutted air has access-to the interior of a luminaire until the inner gas pressure surpasses the ambient pressure. Either air or an inert gas, e.g., nitrogen can be used as a filler medium. An inert gas would have the advantage of preventing oxidation of the reflector and of reducing the deterioration of the gasket and other parts as well. A minimal pressure head must be present at the lowest temperature.

The pressurization of the interior of the luminaire prevents inside deposits and corrosion as long as the pressure is maintained. Should, however, the pressure inadvertently cease to exist,-e.g., due to a leakage, the ambient air would have again free access to the interior as described above. Therefore, it is necessary to provide each luminaire with a pressure indicator. Different forms of these can be used, depending on'the location of the luminaire with respect to the observer. If the luminaire is close to the observer, a simple rubber or plastic balloon connected with the interior of the luminaire can be used the inflated stage of which indicates the presence of inside pressure. Its collapse shows the lack of pressure.

In the case of street and roadway lighting luminaires with greater mounting heights a pressure indicator combined with a small electric lighting bulb can be used. This is switched on by means of a membraneoperated electric switch in case of the absence of inner pressure. Otherwise the small indicator lamp is out of operation. In another embodiment of my invention, a pressure indicator which is a combination of a membrane and an electronic transmitter device can be adapted. The lack of pressure actuates the transmitter through a memberane. Its signals are picked up by a receiver, e.g., anearphone of the observer indicating that the pertinent luminaire has to be checked and possibly fixed. In a further embodiment of my invention, both, the visual and electronic-acoustic indicator can be combined. Other forms, of radio transmitting and receiving devices can also serve to indicate depressurization of the luminaire to the remote observer according to further embodiments of my invention.

The outside of the luminaires can be easily cleaned by means of a mechanical device combined with a spray of water or'detergent possibly mounted as a cherry-picker type device, from street level. Only those luminaires have to be opened, their interiors cleaned and repressurized which have been pinpointed by a pressure indicator according to my invention. This procedure reduces the maintenance and cleaning costs of the lighting equipment to a fraction of their previous amounts. Thereby, its maximum lighting performance is permanently ensured.

Another embodiment of this invention is the use of an inflated gasket which under inner pressure will fill out any gap between the glass or plasticcover'and the A body of the luminaire. In keeping the inflatable gasket under constant pressure the breathing and inner contamination ofthe luminaire will be prevented. The loss of pressure can be indicated by a visual and/or an electronically actuated pressure indicator which can be visual'or acustical as described before.

Such an inflated gasket can be used by itself or in combination with a pressurized luminaire to prevent contamination and corrosion of its inner parts.

The pressurization of the gasket and/or the luminaire can be performed advantageously by means of an electric gas-compressor unit plugged into the outlet, a standard outfit on luminaires provided with a photoelectric cell. Means can be also provided to pressurize the lumi- 1. The necessity of cleaning the inner parts of luminaires can be eliminated completely.

2. Only the outside of the glass or plastic cover has to be cleaned periodically to be performed from street level.

3. The absence of inner pressure and the danger of inner contamination is pinpointed automatically and immediately.

4. Only luminaires with uptight sealings have to undergo maintenance.

5. Lasting maximum light output of the lighting equipment is achieved at substantially reduced cost.

6. Maintenance can be easily controlled.

FIGS. 1 to 6 show advantageous embodiments of my invention.

FIG. 1 shows a cross section of a luminaire equipped with a pressure indicator consisting of a rubber or plastic baloon connected with the interior of the luminaire.

FIG. 2 is a detail of a rubber or plastic balloon pressure indicator.

FIG. 3 is a cross section of a lighting luminaire combined with a pressure indicator consisting of a membrane which actuatesan electric switch to switch on a small electric bulb in case of the absence of gas pressure inside the luminare.

FIG. 4 is'a detail of the visual pressure indicator according to FIG. 3.

FIG. 5 is a detail of a radio-transmitting pressure indicator.

FIG. 6 shows an inflatable gasket on a luminaire in combination with a pressure indicator.

In FIG. I the digit 1 indicates the body of an airtight luminaire; 2'is a light bulb, 3 a glass or plastic refractor cover, 4 a reflector, 5 a photoelectric cell to switch on the light bulb 2 at the approach of darkness, and switch it off at dawn. A rubber or plastic balloon 6 is connected with the interior 7 of the luminaire 1 through a hole 8 of a connecting piece 9 attached to the body 1. The connecting piece has a branch 10 in which a ball check valve 11 is provided with connecting end 16 through which compressed air or gas can be pumped into the interior of the luminaire-and into the balloon 6. The same check valve will prevent the compressed gas from escaping. The luminaire can be advantageously pressurized by plugging in an electric gas- 'ergize the photoelectric cell 5.

In FIG. 2 two sealing rings are denoted by 12, a nut fitting into the thread of the connecting piece 9 by 13, and a translucent protecting glass or plastic cover by 14. The balloon 6 is tightly attached to the mouthpiece 15 of the connecting piece 9. An inflated balloon indicates the presence of gas pressure, and a collapsed balloon indicates the absence of gas pressure.

In FIG. 3 a membrance and distribution box is denoted by 18, a T-piece connecting the latter with the interior 7' of the luminaire and intermittently with a pressure source, not shown, by 17, a check valve by 11, a connecting end by 16', a small light bulb on the membrane and distribution box by 19, and its translucent protective cover by 20. The membrane and distribution box is advantageously plugged in into an outlet 21 on the top of the luminaire. A similar outlet 22 is arranged on the top of the box 18 to plug in a photoelectric cell 5 for the control of lamp 2'. The same outlet can be used to provide power for an electric gascompressor to pressurize the luminaire through connecting end 16', check-valve 11', and T-piece 17. For the duration of this procedure, the photoelectric cell has to be temporarily removed and only plugged 'in again when the pressurization is completed.

In FIG. 4 the membrane and distribution box 18 contains a membrane 23 which, if under gas pressure, interrupts contacts 25, 26 by moving a spring 24 in the counterclockwise direction around contact point 29. The membrane allows the spring 24 to move in the clockwise direction, if deflated thereby closing the contacts 25, 26 and energizing the electric lamp 19 through the contacts 27, 28, the lamp socket 37, contacts 32, 33, and 29, 30, furthermore through two of the plugs of the outlet 21. Contacts 32, 36, and 31, 35, as well as 30, 34 are interconnected to provide electricity for the outlet 22 into which the photoelectric cell 5 or an electric gas-compressor unit can be plugged in. v

The lamp socket and lamp 19 can be replaced by an electric buzzer in a way well known in the art in order to provide an electro-acoustic signal indicating the absence of gas pressure.

In FIG. 5 a membrane and distribution box 18" is connected with the inner space of the luminaire l the same way as described before through T-piece 17". When depressurized, a membrane 23" linked to a rod 38 moves to the right and thereby the position of the latter is changed with respect to a coil 39 forming part of a tuning circuit of a radio transmitter 40. The displacement of the rod 38 causes the change in the value of the reactance of the coil which than actuates the radio transmitter 40. The electromagnetic waves emitted from the transmitter energize the receiver of the observer indicating a lack of pressure.

As an alternate to this embodiment, well known in the art, the capacity of a condenser of a tuning circuit of the radio transmitter can be similarly changed through the motion to the right of membrane 23" which causes the radio transmitter to emit electromagnetic waves actuating the receiver of the observer.

As long as theluminaire is under gas pressure, the membrane 23" is inflated and in neither of these embodiments are electromagnetic waves tuned to the receiver emitted from the radio transmitter 40.

FIG. 6 shows a partial cut through and a perspective view of a luminaire 1". In this 2" represents a lamp, 4" is a reflector, 3" a translucent refractor cover, 18" a membrane and distribution box on the top of the luminaire, plugged in into an outlet 21", an inflatable gasket between body 1" and cover 3 by 41, a tube connecting it with box 18" by 42, and a connecting end for a pressure source by 16".

The arrangement of the membrane and distribution box 18" is identical with that of FIG. 4. Gasket 41 provides a tight sealing of the interior as long as it is inflated adequately. If it is deflated, the membrane in the box 18" causes to close the electric circuit of lamp 19" and then its light indicates this to the remote observer.

I claim:

1. In a luminaire comprising a housing and a cover defining a sealed interior adapted to contain a first fluid under pressure, an illumination source within said interior having the effect of heating and thereby increasing the pressure of said first fluid when operating, means for supplying electrical operating power to said illumination source, a device for indicating a loss of gas pressure within said interior, said indicating device comprising a chamber external to but in fluid communication with said interior, and pressure sensitive control means in said chamber for operating said indicating device when the pressure in said interior falls below a predetermined level while said illuminating source remains operational, and means for establishing a seal along the entire circumferential sealing surfaces of said housing and said cover including a resilient gasket having an outer wall extending along the sealing surfaces and including a hollow interior, and means for introducing a second fluid under pressure into said hollow interior of said gasket to cause said walls of said gasket to press against said sealing surfaces,'whereby a uniform pres sure is established along the entire sealing surface of said cover irrespective of the pressure of said first fluid.

2. The combination of claim 1, in which said indicating device is electrically operated, said control means including operating means operable between a first condition in which said indicating device is inoperative to a second condition in which said indicating device is operative, and pressure-sensitive means operatively connected to said operating means for placing said operating means in its said second condition to operate said indicating device when said pressure falls below said predetermined level.

3. In the luminaire of claim 1, further comprising means for indicating the reduction of fluid pressure within the interior of said gasket below a predetermined value. v

4. In the luminaire of claim 1, in which said operating means includes switching means including a normally open contact, and a pressure-sensitive member normally urging said contact in an open position.

5. In the luminaire of claim 3, further comprising a fluid conduit connecting the interior of said gasket to said chamber.

6. In the luminaire of claim 5, in which said fluid introducing means includes an inlet end in fluid communication with said fluid conduit.

7. In a luminaire comprising a housing and a cover defining a sealed interior adapted to contain a first fluid under pressure, an illumination source within said interior having the effect of heating and thereby increasing the pressure of said first fluid when operating, and means for supplying electrical operating power to said illumination source, a device for indicating a loss of gas pressure within said interior, said indicating device comprising a chamber external to but in fluid communication with said interior, and pressure sensitive control means in said chamber for operating said indicating device when the pressure in said interior falls below a predetermined level while said illuminating source remains operational.

8. In a luminaire comprising a housing and a cover defining a sealed interior adapted to contain a first fluid under pressure, an illumination source within said interior having the effect of heating and thereby increasing the pressure of said first fluid when operating, and means for establishing a seal along the entire circumferential sealing surfaces of said housing and said cover including a resilient gasket having an outer wall extending along the sealing surfaces and including a hollow interior, and means for introducing a second fluid under pressure into said hollow interior of said gasket to cause said walls of said gasket to press against said sealing surfaces, whereby a uniform pressure is established along the entire sealing surface of said cover irrespective of the pressure of said first fluid. 

1. In a luminaire comprising a housing and a cover defining a sealed interior adapted to contain a first fluid under pressure, an illumination source within said interior having the effect of heating and thereby increasing the pressure of said first fluid when operating, means for supplying electrical operating power to said illumination source, a device for indicating a loss of gas pressuRe within said interior, said indicating device comprising a chamber external to but in fluid communication with said interior, and pressure sensitive control means in said chamber for operating said indicating device when the pressure in said interior falls below a predetermined level while said illuminating source remains operational, and means for establishing a seal along the entire circumferential sealing surfaces of said housing and said cover including a resilient gasket having an outer wall extending along the sealing surfaces and including a hollow interior, and means for introducing a second fluid under pressure into said hollow interior of said gasket to cause said walls of said gasket to press against said sealing surfaces, whereby a uniform pressure is established along the entire sealing surface of said cover irrespective of the pressure of said first fluid.
 2. The combination of claim 1, in which said indicating device is electrically operated, said control means including operating means operable between a first condition in which said indicating device is inoperative to a second condition in which said indicating device is operative, and pressure-sensitive means operatively connected to said operating means for placing said operating means in its said second condition to operate said indicating device when said pressure falls below said predetermined level.
 3. In the luminaire of claim 1, further comprising means for indicating the reduction of fluid pressure within the interior of said gasket below a predetermined value.
 4. In the luminaire of claim 1, in which said operating means includes switching means including a normally open contact, and a pressure-sensitive member normally urging said contact in an open position.
 5. In the luminaire of claim 3, further comprising a fluid conduit connecting the interior of said gasket to said chamber.
 6. In the luminaire of claim 5, in which said fluid introducing means includes an inlet end in fluid communication with said fluid conduit.
 7. In a luminaire comprising a housing and a cover defining a sealed interior adapted to contain a first fluid under pressure, an illumination source within said interior having the effect of heating and thereby increasing the pressure of said first fluid when operating, and means for supplying electrical operating power to said illumination source, a device for indicating a loss of gas pressure within said interior, said indicating device comprising a chamber external to but in fluid communication with said interior, and pressure sensitive control means in said chamber for operating said indicating device when the pressure in said interior falls below a predetermined level while said illuminating source remains operational.
 8. In a luminaire comprising a housing and a cover defining a sealed interior adapted to contain a first fluid under pressure, an illumination source within said interior having the effect of heating and thereby increasing the pressure of said first fluid when operating, and means for establishing a seal along the entire circumferential sealing surfaces of said housing and said cover including a resilient gasket having an outer wall extending along the sealing surfaces and including a hollow interior, and means for introducing a second fluid under pressure into said hollow interior of said gasket to cause said walls of said gasket to press against said sealing surfaces, whereby a uniform pressure is established along the entire sealing surface of said cover irrespective of the pressure of said first fluid. 